One Ohm Resistor Separating Grounds?

[ammel68]

I recently purchased a headphone amp PCB which uses two OPA2134's and a TPA6120.

The audio input ground is connected to the power supply ground through a 1 ohm resistor.
Only the feedback resistors for the 2134's and the 6120 are connected to the audio input ground.
All other components including the headphone output, are connected to the ground plane connected to the power supply ground.

Can someone explain what the theory is behind this?

Thanks...

 

[DUG]

Ground loops...where some of the higher current traveling in the ground path affects a small signal that has the same common ground path.

Much theory and debate as to the best way to minimize this problem.

🙂

 

[ammel68]

Does the 1 ohm resistor, connecting both grounds, prevent ground loops somehow?

 

[DUG]

Reduces.